In general, Mg-based alloys consisting essentially of Mg have been produced in a solubilization process using alloy elements such as Al, Zn and the like which have a larger solubility to Mg. These alloys include Mg-Al-Zn type alloys. Such Mg-based alloys are excellent in specific strength and vibration absorbing capacity (damping capacity), but poor in corrosion resistance.
Therefore, development of various Mg-based alloys has recently been made in order to provide a Mg-based alloy having a high strength and an excellent corrosion resistance.
It is generally difficult to produce a Mg-based alloy containing a relatively large content of an alloy element having a small solubility to Mg.
More recently, a Mg-Zr-Zn type alloy and a Mg-Zr-rare earth element type alloy have been developed by partially overcoming this difficulty. They can be produced by utilizing the fact that Mg-Zr based alloys belong to a group of alloys resulting from a peritectic reaction.
In practice, however, the Mg-Zr type alloys containing a large content of Zr have still been very difficult to produce in a solubilization process.
Accordingly, it is further desired to develop a Mg-based alloy which can be readily produced using other alloy elements in place of Zr and the like and which is excellent in properties. Ti has been regarded as an alloy element satisfying such a demand. Thus, attempts have been made to produce a Mg-Ti based alloy, because Ti belongs to the same Periodic group as Zr.
However, Ti is an element having a small solubility to Mg, and alloys containing Ti at a concentration of up to merely 0.125% by weight are shown in the phase diagrams for Mg-Ti based alloys reported by Hansen. These phase diagrams are not for the practical alloys, but have been only drawn by estimation lines, because the solubility of Ti to Mg is extremely small. Therefore, a definite phase diagram has been still not cleared. In these phase diagrams, the solubility of Ti to Mg is shown to be extremely small, i.e., 0.0025% by weight (0.0013 atom %) at 651.degree. C. immediately above the melting point (650.degree. C.) of Mg and 0.015% by weight at 850.degree. C.
Thus, up to date, it has been impossible to produce a Mg-Ti based alloy containing Ti of a high concentration, and in practice, no Mg-Ti based alloy containing Ti of a high concentration has been produced.
It is required on all accounts and desired to develop a Mg-Ti type alloy and a method for production thereof, because the Mg-Ti type alloy is regarded as an alloy providing an effect similar to that of the Mg-Zn type alloy and thus, having a high strength, a high damping capacity and the like.